Portable tube bender



May 31, 1966 M. R. TOBIAS PORTABLE TUBE BENDER 2 Sheets-Sheet 1 Filed Dec. 2'7, 1962 INVENTOR.

MELVIN R. TOBIAS ATTORNEY 2 Sheets-Sheet 2 M. R. TOBIAS PORTABLE TUBE BENDER May 31, 1966 Filed Dec. 27, 1962 Oh NN INVENTOR MELVIN R. TOBIAS ATTORNEY United States Patent 3,253,450 PORTABLE TUBE BENDER Melvin R. Tobias, Signal Mountain, Tenn., assignor to Combustion Engineering, Inc., Windsor, Conn, a corporation of Delaware Filed Dec. 27, I962, Ser. No. 247,656 4 Elaims. (Cl. 72318) This invention relates to tube benders and more particularly, to tube benders of the type comprising a hydraulically operated, movable ram for exerting a bending force on a tube and a fixed bending shoe cooperating therewith to produce a bend in said tube.

Tube benders capable of exerting sufficientforce to bend heavy metal tubes have heretofore been required to employ a rigid base on which to mount the bending apparatus in order that the forces generated by the bender do not render it unstable. Because of this fact it has been impossible to first mount and align the tubes in the installation for which they are intended and thereafter operate on the tube to provide the desired bend therein,

but instead the tubes must first be transported to the bender to be bent and thereafter mounted in the installation. This procedure is undersirable in View of the fact that, after the bent tubes are mounted it sometimes happens that the bend produced in one or more of the tubes may be somewhat inaccurate thereby requiring their removal from the installation and return to the bender to have the error corrected. This operation is cumbersome and requires a considerable amount of time and effort to achieve its intended result thereby increasing the over-all expense of constructing the tubular installation.

The present invention comprehends a new and improved type of bending apparatus capable of bending relatively heavy tubes without the need of separate support means for the bender. The apparatus discussed herein is structurally compact and self-supporting to the extent that it can be mounted on the workpiece upon which it will operate yet is capable of generating sufiicient bending forces to form bends in tubes which are in excess of two inches in diameter. By means of the present invention, tubes can first be mounted in their intended installation, as for example, a header, and thereafter operated on by the bender which is easily transportable and manipulatable to thus greatly reduce the time, effort and expense of constructing tubular installations requiring intricate bends.

It is therefore a principal object of the present invention to provide a tube bender which is structurally compact and operably eflicient.

Another object of the invention is to provide a selfsupporting tube bender capable of generating sufiicient force to bend relatively heavy metal tubes.

A more particular object of the present invention is to provide a tube bender which is so constructed as to enable the reactive force generated during its operation to be utilized to counteract the bending force generated to thereby permit the bender to be supported on the work being operated on thereby eliminating the need for a separate bender support means.

Other and further objects of the invention will become apparent to those skilled in the art as the description proceeds.

With the aforementioned objects in view, the invention comprises an arrangement, construction and combination of the elements of the inventive organization in such a manner as to attain the results desired as hereinafter more particularly set forth in the following detailed description of an illustrative embodiment, said embodiment being shown by the accompanying drawings wherein:

FIGURE 1 is an elevational view, with a portion of 3,253,45d Patented May 31, 1966 one side removed and partly in section, of the tube bender embodied in the present invention;

FIGURE 2 is an end view of the tube bender shown in FIGURE 1;

FIGURE 3'is an isometric representation of the slide assembly including the bending roller employed in the instant invention;

FIGURE 4 is a section taken along line 4--4 in FIG- URE 1;

FIGURE 5 is a pictorial illustration of the tube bender of FIGURE 1 including its carriage and hydraulic operating equipment, mounted for operation on a tubular nipple attached to a header;

FIGURE 6 is a partial elevation of the tube bender of FIGURE 1 having an adapter attached thereto to permit its operation in instances where the bend must occur on a tube or nipple at a position which would preclude the benders bearing on a header to which the work is attached; and

FIGURE 7 is a view taken along line 77 of FIG- URE 6.

Referring now to the drawings, there is shown a tube bender 10 comprising an elongated body 12, a hydraulically operated force imparting roller 14, a stationary bending shoe 16 and an adjustable bearing plate 18. The body 12 consists of a base 20 and side plates 22 which are rigidly mounted to the side edges of the base by means of fasteners 24 and spaced at their upper end by a spacer 25 thereby forming a yoke-like member. The rearward portions of the side plates 22 are formed of a substantially reduced vertical dimension so as to permit the mounting of hydraulic force applying means in operational alignment with guideways 26 formed in the upper portion of the opposed inner surfaces of the side plates 22 at the other end thereof. Attaching the hydraulically operating means to the body is a mounting plate 28 which is attached to the upper edges of the side plates 22 at the rear portion thereof. To the mounting plate is attached, by means of fasteners 30, the hydraulically operating means which consists essentially of a cylinder 32, a piston 34 adapted for reciprocating movement therein and fittings 35 permitting hydraulic communication with the cylinder. To the piston 34 is attached a rod 36 having one end 38 thereof threaded to permit its attachment to a slide assembly or ram 40 which is mounted for reciprocating movement in the guideways 26.

The ram 40 consists of a substantially U-shaped slide member, the sides 4-2 of which contain dovetail bearing surfaces 44 adapted to be received in the guideways 26 of the side plates 22. To the rear end of the ram 4t) is mounted, as by means of welding, a threaded receptacle 46 to receive the threaded end 38 of the piston rod 36. The ram 40 may contain an aperture 48 in alignment with the threaded aperture in the receptacle 46 to provide clearance for the threaded end of piston rod 36. The forward ends of the sides 42 contain curvi-linear recesses 50 to pivotally mount the hereinafter described roller assembly.

The roller assembly comprises a roller 14 formed with an arcuately shaped bearing surface 56 which conforms to the surface of the tube to be bent. The roller is an interchangeable member such that rollers having bearing surfaces of different radii can be employed for use with tubes of different diameters. To pivotally mount the roller 14 in the recesses 50 a pivot pin 52 is press fit within an aperture provided in the roller. The ends of the pin 52 extend beyond the edges of the roller and are adapted to be received within the recesses 50. The curvature of the recesses 50 is such as to retain the roller assembly within the slide member upon retraction thereof; however, latch means (not shown) can be employed to positively prevent removal of the roller from the recesses.

The forward ends of the side plates 22 are also provided on their inner surfaces with opposed-dovetail slots 60 adapted for detachable mounting of an interchangeable bending shoe 16. The bending shoe 16 consists of a block having a surface 64 which contains the curvature of the bend to be made in the tube. The surface 64 is provided with an arcuate groove 66 conforming to and re- 'ceiving the surface of the tube to be bent so as to prevent deformation of the latter during the bending process. While the bending shoe 16 shown in FIGURE 1 is formed to produce a bend of 90 in the tube, bending shoes having angular extents of from O to 90 can be utilized in the bender to produce the various bends desired.

For detachable mounting of the bending shoe 16 to the body 12 the former has its sides formed with dovetail guide ribs 68 which are received within the slots 60 provided in the body 12. To anchor the bending shoe Within the body an anchor pin 70 is provided which is inserted through one of the side plates 22 and received in an aperture 72 in the bending shoe which is aligned with a similar aperture 71 in the side plate when the bending shoe is in its proper position.

A bearing plate 18 is mounted upon the body 12 in such a manner that the reactive force developed in the hydraulic cylinder 32 upon actuation of the piston 34 to bend the tube is transferred from the cylinder through the elongated body by means of the bearing plate to the tube being bent in a manner that tends to counteract the bending force generated by the piston so as to enable the tube bender to operate without the need of separate support means. The bearing plate 18 may take many forms, all that need be provided being a surface which establishes a point of contact through which the reactive forces can 'be transferred to the tube. In the device shown in FIGURE 1 the bearing plate has a surface 74 which is adapted to abut the surface of a header 76, shown in phantom, to which a short nipple 78 is attached. The bearing plate 18 comprises a structural member having a T-shaped upper portion 75 which is received within the T-slot 77 formed between the spaced side plates 22 in the body 12. The bearing plate 18 is mounted in the body 12 with its bearing surface 74 depending from the bottom thereof and opposed to the operating surface of the bending shoe 16 such that the surface 74 is capable of action on the tube at a point below the point of contact of the bending shoe 16 which, during the bending operation, acts as a fulcrum for the tube being bent. By means of this structural arrangement the reactive force developed in the cylinder 32 is capable of counteracting the bending force generated by the roller 14 upon the tube 78.

The bearing plate 18 is mounted for longitudinal adjustment within the body 12 by means of a threaded adjusting screw 84 which has its inner end 86 mounted within the bearing plate and its threads adapted to be received within a retainer 88 having a threaded aperture therein such that rotation of the adjusting screw effects a longitudinal movement of the bearing plate 18 along the T- slot 77.

As shown in FIGURE 1, the side plates 22 of the body 12 extend forwardly beyond the forward end of the base 20 and present a recess 89 adapted to receive the tube or nipple to be bent. The roller 14 and forward end of the base 20 are so arranged that with the piston 34 in its retracted or inoperable position the bearing surface 56 on the roller is in vertical alignment with the leading end of the base thereby presenting means to vertically align the tube and the bender prior to initiating the bending operation.

The operation of the tube bender is best described with refeernce to FIGURE 5. A header 76 having a plurality of short tubular nipples 78 weldedly attached thereto is held in position by means of vertical stays (not shown) to receive the bender which is transported to the header by means of a dolly 110 mounted on rollers 112. The bender 10 is carried on the dolly 110 by means of a pulley 114 which depends from a jib boom 116. On the dolly 110 is mounted the hydraulic operating apparatus which includes a pump 118, pump motor 120, reservoir tank 122 and fluid lines 124 and 126 which connect the tank 122 to the fittings 35 on the forward and rearward ends of the piston 34. A directional Valve 128 is provided in the lines 124 and 126 and is instrumental in admitting fluid pressure to the cylinder 32 to move the piston to an operative or retracted position.

To form a bend in the nipples 78 the bender, its bending shoe 16 being detached from the body 12, is brought to rest on the header 76 with the side plates 22 straddling the nipple 78 and the nipple flush against the bending surface 56 of roller 54 and the leading end of the base 20.

The adjusting screw 84 is rotated to move the bearing plate 18 inwardly until the bearing surface 74 thereon abuts the header 76. Thereafter, the bending shoe 62 is installed in the body 12 by inserting the guide ribs 68 into th slots until the bearing surface 64 abuts the surface of the nipple thereby bringing the bending shoe aperture 72 into alignment with the aperture 71 in the side plate 22 and inserting the anchor pin therein to prevent movement of the bending shoe within the body. Hydraulic pressure is then admitted to the rear side of the piston 34 through fluid line 124 to move the piston and thereby the rod 36 and roller 54 along the path of reciprocation defined by the guideways 26 thus exerting a bending force upon the nipple 78 causing it to be bent about the surface 64 formed on the bending shoe 16.

While the bending force is being exerted against the nipple 78 by the fluid within the cylinder 32 there is an equal and opposite reactive force acting against the rear end 90 thereof and, because the cylinder 32 is rigidly mounted to the body 12, this reactive force is transferred through the body 12 to the header 76 and nipple 78 which is rigidly attached thereto since the bearing plate 18 is in abutment with the header 76. Therefore, with the bend ing shoe 1'6 acting as a fulcrum there is developed in the nipple and header assembly a pair of equal and opposite bending moments about the bending shoe 16 which result in a force system maintained in equilibrium. Because the system of forces generated by the tube bender is maintained in equilibrium, there is no need to provide a separate support means having for its purpose the stabilization of the bending operation and the bender can be directly mounted to the workpiece on which it is intended to operate.

When it is desired to form a bend in a tube or nipple at a point distantly removed from the header or where the tube is detached from the header, a special adapting means can be mounted in fixed relation to the body 12 such that an abuting surface can be brought to bear against that portion of the tube located on the opposite side of the bending shoe 16 from the point of application of the roller 14 thereby establishing a force system comprising equal and opposite moments with respect to the nipple about the bending shoe to maintain the system of forces and the tube bender in equilibrium. This adapting means consists of a bifurcated adapted 92 which can be mounted to the bending shoe 16 by means of fasteners 94. The adapter has a bearing surface 96 of a curvature which conforms to the surface of the tube and is mounted such that the bearing surface is in alignment with the bearing surface 64 on the bending shoe 16. The adapter sides 98 which form a bifurcate are apertured at 100 to mount to the adapter 92 a retainer 102 which has an arcuate innet surface 104 complementing the bearing surface 96 of the adapter to form a surface which conforms to and is capable of snugly circumventing the surface of the tube or nipple. The retainer 102 is provided with an aperture 103 which, when the retainer is mounted on the adapter 92, is adapted to be aligned with the apertures 100. A retainer pin 106 is inserted through the aligned apertures 100 and 103 to anchor the retainer to the adapter.

In operation, the bender, when using the special adapting means, is mounted to the tube in the same manner as hereinbefore described except that the bearing plate 18 is either moved to a retracted position or removed entirely from the body 12. When the tube is aligned within the body, the bending shoe 16 having the adapter 92 mounted thereon is attached to the body 12 by means of the anchor pin 70 and thereafter, the retainer 88 which is formed of a size to be received between the spaced sides 98 of the adapter is inserted therebetween with its arcuate surface 104 brought to bear against the surface of the tube and the retainer pin 106 inserted through the apertures 100 and 103 to complete the assembly. Hydraulic fluid is then admitted to the cylinder 32 creating a force generated by the roller 14 which causes the tube to be bent around the bending shoe 16. At the same time the reactive force generated on the rear side 90 of the cylinder is transferred through the body 12 and exerted on the tube through the tube retainer 102 to thus establish an equal and opposite bending moment on the tube which maintains the entire system in equilibrium.

From the foregoing it can be seen that the present invention provides a compact tube bender capable of exerting sufficient force to bend relatively heavy metal tubes in a highly efficient manner. The tube bender, which is structurally simple and easy to fabricate, can be mounted directly upon the tube to be bent and receive its sole support from the tube and header assembly thereby rendering the apparatus substantially self-supporting.

While I have illustrated and described a preferred embod-iment of my invention it is to be understood that such is merely illustrative and not restricted and that variations and modifications may be made therein without departing from the spirit and scope of the invention. I therefore do not wish to be limited .to the precise details set forth but desire to avail myself of such changes as fall within the purview of my invention.

What I claim is:

1. A portable tube bender engageable with a tubular workpiece comprising a base having spaced arms defining a yoke adapted to receive a tube, a bending shoe detachably mounted between said arms having a tube-engaging groove defining a desired bend disposed about an axis, bending means including a ram movable toward said bending shoe, guide means in said arms for directing said ram along a line spaced from said axis, roller means having a tube-engaging groove complementary to and confronting that of said bending groove detachably, pivotally mounted to said ram, force imparting means including a fluid cylinder attached to said base, a piston operable in said cylinder and attached to said ram for reciprocating said ram along said line, and bearing means mounted to said base having a bearing surface opposed to said bending shoe groove engageable with said workpiece on the opposite side of said axis from said line.

2. A tu-be bender as recited in claim 1 wherein said bearing means comprises a member adjustably mounted for longitudinal movement toward and away from the tube-engaging groove of said bending shoe.

3. A tube bender as recited in claim 1 wherein said bearing means comprises an adapter detachably mounted to said bending shoe, said adapter depending from said bending shoe and having a tube-engaging groove in alignment with that of said bending shoe, and a retainer detachably mounted to said adapter and having a groove complementary to and confronting that of said adapter.

4. A portable tube bender engageable with a tubular workpiece cnmprising a base having spaced arms defining a yoke adapted to receive a tube, a bending shoe detachably mounted between said .arms having a tube-engaging groove defining a desired bend disposed about an axis, bending means including a ram movable toward said bending shoe, guide means in said arms for directing said ram .along a line spaced from said axis, roller means having a tube-engaging groove complementary to and confronting that of said bending shoe detachably, pivotally mounted to said ram, force imparting means attached to said base and engaging said ram for linearly moving said ram along said line, and means mounted to said base having a bearing surface opposed to said bending shoe groove engageable with said workpiece on the opposite side of said .axis from said line.

References Cited by the Examiner UNITED STATES PATENTS 279,618 6/1883 Wells 153--38 1,136,463 4/1915 Bodkin 153-38 1,172,332 2/1916 Williams 15338 1,390,107 9/1921 Pagan 15338 1,8=44,724 2/1932 Tomlin 15338 1,935,055 11/193 3 Morgan 153-15 X 2,382,266 8/1945 Simonsen 15338 2,801,559 8/1957 Hawes 15338 X CHARLES W. LANHAM, Primary Examiner.

RONALD D. GREFE, Assistant Examiner. 

1. A PORTABLE TUBE BENDER ENGAGEABLE WITH A TUBULAR WORKPIECE COMPRISING A BASE HAVING SPACED ARMS DEFINING A YOKE ADAPTED TO RECEIVE A TUBE, A BENDING SHOE DETACHABLY MOUNTED BETWEEN SAID ARMS HAVING A TUBE-ENGAGING GROOVE DEFINING A DESIRED BEND DISPOSED ABOUT AN AXIS, BENDING MEANS INCLUDING A RAM MOVABLE TOWARD SAID BENDING SHOE, GUIDE MEANS IN SAID ARMS FOR DIRECTING SAID RAM ALONG A LINE SPACED FROM SAID AXIS, ROLLER MEANS HAVING A TUBE-ENGAGING GROOVE COMPLEMENTARY TO AND CONFRONTING THAT OF SAID BENDING GROOVE DETACHABLY, PIVOTALLY MOUNTED TO SAID RAM, FORCE IMPARTING MEANS INCLUDING A FLUID CYLINDER ATTACHED TO SAID BASE, A PISTON OPERABLE IN SAID CYLINDER AND ATTACHED TO SAID RAM FOR RECIPROCATING SAID RAM ALONG SAID LINE, AND BEARING MEANS MOUNTING TO SAID BASE HAVING A BEARING SURFACE OPPOSED TO SAID BENDING SHOE GROOVE ENGAGEABLE WITH SAID WORKPIECE ON THE OPPOSITE SIDE OF SAID AXIS FROM SAID LINE. 